In a recent study, scientists have shown that red blood cells were preserved in Iceman tissue samples for more than 5,000 years. The morphological and molecular composition of the blood corpuscle has been verified by atomic force microscope and Raman spectroscopy measurements.

His
DNA has been decoded; samples from his stomach and intestines have
allowed us to reconstruct his very last meal. The circumstances of his
violent death appear to have been explained. However, what had, at least
thus far, eluded the scientists, was identifying any traces of blood in
Ötzi, the 5,000 year old glacier mummy. Examination of his aorta had
yielded no results. Yet recently, a team of scientists from Italy and
Germany, using nanotechnology, succeeded in locating red blood cells in
Ötzi’s wounds, thereby discovering the oldest traces of blood to have
been found anywhere in the world.

“Up
to now there had been uncertainty about how long blood could
survive—let alone what human blood cells from the Chalcolithic period,
the Copper Stone Age, might look like.” This is how Albert Zink, Head of
the Institute for Mummies and the Iceman at the European Academy,
Bozen-Bolzano (EURAC) explains the starting point for the investigations
which he undertook with Marek Janko and Robert Stark, materials
scientists at the Center of Smart Interfaces at Darmstadt Technical
University.

Even
in modern forensic medicine it has so far been almost impossible to
determine how long a trace of blood had been present at a crime scene.
Scientists Zink, Janko and Stark are convinced that the
nanotechnological methods which they tested out on Ötzi’s blood to
analyse the microstructure of blood cells and minute blood clots might
possibly lead to a break-through in this area.

The
team of scientists used an atomic force microscope to investigate thin
tissue sections from the wound where the arrow entered Ötzi’s back and
from the laceration on his right hand. This nanotechnology instrument
scans the surface of the tissue sections using a very fine probe. As the
probe moves over the surface, sensors measure every tiny deflection of
the probe, line by line and point by point, building up a
three-dimensional image of the surface. What emerged was an image of red
blood cells with the classic “doughnut shape”, exactly as we find them
in healthy people today.

“To
be absolutely sure that we were not dealing with pollen, bacteria or
even a negative imprint of a blood cell, but indeed with actual blood
cells, we used a second analytical method, the so-called Raman
spectroscopy method”, report Marek Janko and Robert Stark, who, with
Albert Zink, are also members of the Center for NanoSciences in Munich.

In
Raman spectroscopy the tissue sample is illuminated by a laser beam and
analysis of the spectrum of the scattered light allows one to identify
various molecules. According to the scientists, the images derived from
this process corresponded to present-day samples of human blood.

Whilst
examining the wound at the point where the arrow entered the body, the
team of scientists also identified fibrin, a protein involved in the
clotting of blood. “Because fibrin is present in fresh wounds and then
degrades, the theory that Ötzi died some days after he had been injured
by the arrow, as had once been mooted, can no longer be upheld,”
explains Albert Zink.            

Preservation of 5300 year old red blood cells in the Iceman

Source: EURAC